Course Planning

using System;
using System.Collections.Generic;
using System.Linq;

namespace ListEx10Course
{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> list = Console.ReadLine().Split(", ", StringSplitOptions.RemoveEmptyEntries).ToList();
            string commands;

            while ((commands = Console.ReadLine()) != "course start")
            {
                string[] text = commands.Split(':');


                if (text[0] == "Add" && !list.Contains(text[1]))
                {
                    list.Add(text[1]);
                }
                else if (text[0] == "Insert" && !list.Contains(text[1]))
                {

                    list.Insert(int.Parse(text[2]), text[1]);


                }
                else if (text[0] == "Remove" && list.Contains(text[1]))
                {
                    list.Remove(text[1]);
                    if (list.Contains($"{text[1]}-Exercise"))
                    {
                        list.Remove($"{text[1]}-Exercise");
                    }

                }

                else if (text[0] == "Swap" && list.Contains(text[1]) && list.Contains(text[2]))
                {
                    int firstLessonIndex = list.IndexOf(text[1]);
                    int secondLessonIndex = list.IndexOf(text[2]);
                    list[firstLessonIndex] = text[2];
                    list[secondLessonIndex] = text[1];
                    if (list.Contains($"{text[1]}-Exercise"))
                    {
                        list.Insert(secondLessonIndex + 1, $"{text[1]}-Exercise");
                        list.RemoveAt(firstLessonIndex + 2);
                    }
                    if (list.Contains($"{text[2]}-Exercise"))
                    {
                        list.Insert(firstLessonIndex + 1, $"{text[2]}-Exercise");
                        list.RemoveAt(secondLessonIndex + 2);
                    }
                }
                else if (text[0] == "Exercise" && !list.Contains($"{text[1]}-Exercise"))
                {
                    if (!list.Contains(text[1]))
                    {
                        list.Add(text[1]);
                        list.Add($"{text[1]}-Exercise");
                    }
                    else
                    {
                        int indexOfLesson = list.IndexOf(text[1]);
                        list.Insert(indexOfLesson + 1, $"{text[1]}-Exercise");
                    }
                }



            }
            for (int i = 0; i < list.Count; i++)
            {
                Console.WriteLine("{0}.{1}", i + 1, list[i]);
            }
        }
    }
}